MADISON, Wis. -

Wisconsin Department of Transportation officials said the bitterly cold and snowy winter means drivers will need to be extra alert for potholes.

According to a release, the frost depths of 5 feet or more caused by the extreme cold has resulted in pavement movement and heaving.

“Once temperatures finally warm up, most of the tenting should level off, but it will still result in pavement cracking, and every crack is a potential pothole waiting to happen,” Todd Matheson, with WisDOT’s Bureau of Highway Maintenance, said in the release.

Potholes form when moisture enters cracks in pavement and the water freezes and expands, according to the release. Warmer temperatures and traffic can loosen the pavement, causing pieces to break free.

Compared to an average winter, this season has seen a 60 percent increase in the number of winter storm events, officials said. As moisture from continued snowfalls melts, it can enter pavement cracks, freeze and create the perfect conditions for potholes.

“When they’re not plowing and salting to keep the roadways open, highway workers are busy making temporary pothole repairs,” Matheson said. “The best thing drivers can do is slow down and be alert for rapidly changing road conditions. And when you see highway workers making repairs, slow down or move over.”

WisDOT officials have also issued revised guidelines to county highway departments aimed at keeping the highways safe for winter travel, while ensuring an adequate supply of road salt is available for the rest of the winter.

“This winter has been particularly tough on plow operators and equipment, salt supplies and highway pavements,” Mathewson said. "Due to the extreme winter weather, the department is proactively taking a number of steps to extend salt supplies while keeping highways safe and open for travel.”

Some of the steps being taken include reducing salt application on non-interstate routes, increasing an emphasis on pre-wetting salt to help it adhere to the roads and allowing counties to use sand and salt mixtures on lower-volume roads. Officials said there will not be any changes to the level of service on interstate highways.

Average salt use on the State Highway System is about 500,000 tons per year, according to the release. At the beginning of this season 775,000 tons of salt were available and about 135,000 tons remain.